Host URL rewrite with different hostname and static URI

I don't believe this would work because you would constantly be sent back to HTTP path "/site1/login" or "/site2/login" depending on what you HTTP host is. Now you could do something where you check the HTTP path or uri and add "/site1/" or "/site2" to the beginning of the path and if you receive just "/" then send them to the login page. Is your intent to have "/site1/" and "/site2" added to the beginning of their respective path or uri?